The present disclosure relates to a shift-by-wire type control device.
As a shift-by-wire type control device, there is known a control device described in JP 2013-104463 A. A control target of the control device described in JP 2013-104463 A is an automatic transmission including a parking lock mechanism, and the control device operates in response to an instruction from a range selection device in which selection of a shift range is not identified by the mechanical position of a to-be-operated part. Meanwhile, there is a case in which due to instantaneous power interruption of the control device, etc., the control device is reset and abnormally activated (reactivated), and in a shift-by-wire type using a range selection device such as that described above, when the control device is abnormally activated, a shift range having been selected before the abnormal activation cannot be identified from the mechanical position of the to-be-operated part. In addition, in a parking lock device (50) described in JP 2013-104463 A, a detent plate (62) is switched between two positions: a position in which the parking lock device (50) is placed in a locked state, and a position in which the parking lock device (50) is placed in an unlocked state. In such a configuration, even though it can be identified whether the shift range having been selected before abnormal activation is a parking range or a non-parking range from the state of the parking lock device (50), when the selected shift range is the non-parking range, it cannot be identified which one of a forward range, a reverse range, and a neutral range is the shift range from the state of the parking lock device (50).
In view of a problem specific to the shift-by-wire type control device such as that described above, JP 2013-104463 A describes a technique for appropriately setting a shift range after returning from a reset state of the control device. Specifically, JP 2013-104463 A describes that in order to suppress the occurrence of a strange noise caused by the parking lock device switched from an unlocked state to a locked state in a state of a high vehicle speed, when the vehicle speed upon returning from a reset state is higher than a preset threshold, the shift range is set to the neutral range. However, in such a configuration, even if the vehicle has been traveling (traveling at a higher speed than the above-described threshold) in the forward range before abnormal activation of the control device, the automatic transmission is switched to a neutral state after the abnormal activation of the control device, and thus, there is a possibility that driver's drivability may decrease, e.g., a driver perceives a loss of drive power. Hence, it is desired that when a reset of the control device has occurred, a state before the reset be able to be maintained, but in a configuration such as that described above, when a reset of the control device has occurred during traveling of the vehicle, a distinction between a neutral state and a forward range state has not been able to be made.